Over the last few weeks, the brutal torture, rape, and murder of Imette St. Guillen has raised countless questions – not only about the crime, but about our way of life in New York City. In most places throughout the country, bars are shut tight by 4 a.m. Here, nightlife is still bustling at the hour bartenders call last call.

St. Guillen disappeared at closing time on February 25. She’d left alone, we were first told, prompting fears of Mexico City-style abductions. But if The Falls’ bouncer killed her, as the police and prosecutors now say, New Yorkers can feel some relief that a homicidal maniac isn’t roaming around in a van looking for the next victim to pluck from SoHo.

Darryl Littlejohn will be formally charged in the case next week, when a Grand Jury returns the inevitable indictment. Perhaps then we’ll have a better sense of the evidence against him.

What follows are some lingering questions:

Why did St. Guillen refuse to go home with her friend at 3:30 a.m.?

Some people object to asking this question, arguing the premise suggests the victim might be at fault. Let me be clear: St. Guillen did nothing wrong. But her decision to stay out alone in the middle of the night is unusual – there just aren’t that many young women sitting alone at the bar when last call rolls around. Figuring out why St. Guillen stayed out – whether she just felt like having another couple of drinks, whether she was meeting a friend, whether she was hoping to make a new friend – will help us understand how she wound up in a place that she had every right to be but in the end proved deadly.

What was Littlejohn’s job at The Falls?

He’s routinely described as a bouncer, but that doesn’t tell us if he was the muscle stationed inside to break up fights or stationed outside simply checking I.D.’s. Working inside would mean he was there for security purposes and needed a state license (which he didn’t have). Working outside could classify him as something other than “security” in legal terms. Either way, though, as a convicted felon he shouldn’t have been working at the bar. And his employment at The Falls raises obvious concerns about how many other bars illegally employ felons.

Why didn’t state parole and federal probation officials know he was working as a bouncer?

The second part is easy – Federal officials completely dropped the ball on supervising Littlejohn. But state officials were tracking him, including scheduled meetings and unannounced visits to his Queens home. These visits failed to catch Littlejohn violating his 9 p.m. curfew. Perhaps this case is a wake-up call for state authorities to improve their monitoring policies.

Why did the bar mislead police?

Daniel Dorrian, the owner’s brother, first told detectives that Ms. St. Guillen left alone. Nearly a week later, he changed his story and said he asked Littlejohn to walk her out because she was drunk and unwilling to leave. So far, the presumption has been that Mr. Dorrian’s first account was untrue. But Littlejohn’s defense team is already suggesting that perhaps the second version – the version that has Littlejohn escorting St. Guillen out – is inaccurate.

Mr. Dorrian’s elastic recollections jeopardized the murder investigation and gave Littlejohn, if he’s guilty, a long period of time to destroy evidence. Perhaps Mr. Dorrian was lying to protect himself or his family’s bar from scrutiny. Determining his motive to mislead will help determine what part of his story we should now believe.

Does the Dorrian family have a cooperation agreement with authorities?

The NYPD asked the State Liquor Authority and city prosecutors to back off because detectives needed the Dorrians’ help, as I reported nearly a week ago. Given the possibility of obstruction of justice charges given Mr. Dorrian’s inconsistent statements, there could be an immunity deal in the works. We do know the bar is still open despite obvious violations.

What time, and where, was St. Guillen murdered?

Initial reports indicated she was alive until the afternoon, perhaps for 10 hours after she disappeared. Determining what happened after she disappeared from The Falls is a big missing link in this case.

What was St. Guillen’s blood-alcohol content?

Again, this question sends shudders through those who say the victim’s activities are irrelevant. But understanding her level intoxication will help us understand how she wound up in a deadly situation. It will also help her family determine bar owners’ civil liability for continuing to serve someone who may have been visibly drunk.

How did Littlejohn spend the 17 hours between St. Guillen’s 4 a.m. disappearance and the 8 p.m. discovery of her body?

His lawyer claims he doesn’t need an alibi. Of course he does. He’s a murder suspect about to be indicted.

Who called 911 to report a body in a Brooklyn marsh?

No one seems to think the caller was Littlejohn. The caller could be a significant witness.

Why did so much information about the case leak out?

The initial report, buried in a Monday edition of the New York Post, included very detailed information that St. Guillen was found showing signs of sexual assault and a sock stuffed in her throat, her face wrapped in packing tape, her hands and feet tied and her hair cut. NYPD brass were furious such specific information, presumably known only to detectives and the killer, was quickly in the public domain.

Why is there so little DNA evidence from such a violent crime?

So far, the only DNA linking Littlejohn to the case is on a wire binding St. Guillen’s hands. Investigators have not found any of Littlejohn’s DNA on her actual body.

Could Littlejohn be linked to other crimes?

Police think he was involved in two rapes and a kidnapping last year that also yielded very little forensic evidence. But the victims did not pick Littlejohn out of lineups.

Why did Police Commissioner Kelly call a rare Sunday press conference to confirm Littlejohn was the prime suspect?

Brooklyn prosecutors handling the murder case initially objected to the unusual public disclosure. They signed on because of the NYPD’s desire to show progress in the case.

Mr. Goldin’s column appears regularly.